Spectrum disorders are labeled as such because the majority of people with a particular diagnosis have all kinds of symptoms that vary from one individual to the next. Autism is considered a spectrum disorder because of that very reason. Children diagnosed with autism are simultaneously diagnosed with autism spectrum disorder because that is its full and complete clinical name.
Autism spectrum disorder means that these children and adults might be high functioning, low functioning, or functioning in the middle of the road or anywhere in between. There is no one level of functionality for autism, but a broad spectrum. This is the first reason why it’s considered a spectrum disorder.
The second reason is that people diagnosed with autism have many levels of communication, many levels of physical ability, many levels of social acuity, many levels of intellectual ability and many levels of emotional expression. Autism isn’t defined by just one level of any of these categories of development because they all exist to some degree in the individuals with autism. Each and every one of these developmental areas wherein autism presents itself is a spectrum of its own, resulting in a spectrum disorder.
When all of these factors are combined, it produces the third reason why autism is considered a spectrum disorder. Doctors can’t pinpoint exactly where on a scale that the children of autism sit. It’s not a precise diagnosis, and it is one that requires a lot of observance by parents to diagnose.
For comparison, let’s look at another diagnosis unrelated to autism, but one which is common amongst women over the age of thirty. Fibromyalgia, an autoimmune disorder which mimics a lot of other illnesses before it is properly diagnosed, has its own spectrum. No one individual that experiences fibromyalgia experiences it in the exact same way as the next. One person might feel the all over aches intensely, while another might feel them intensely only after physical exertion. Another might be fatigued all the time, while at the opposite end of the spectrum the other might be fatigued only a couple days out of every week.
As you can see, a spectrum disorder needs to be thought of more often in terms of an arc with the primary diagnosis as the arc itself and all of the varying levels and symptoms as being just under it, from one extreme to the other. Because autism definitely creates this type of arc, it is a spectrum disorder and it includes other previous disorders that were once thought to be separate and apart from autism. Of course, these include Asperger’s, Crie Du Chat, PDD-NOS and a couple others. These disorders are no longer diagnosed apart from autism, but as a subtype of autism under the autism spectrum. Most children and adults who are now diagnosed or rediagnosed with autism will have autism listed as their primary diagnosis, subtype this or that. For a better understanding about how this works, anyone can consult the current DSM manual and look under autism.